1. Field of the Invention
The present invention relates to a behavior-disrupting agent and a behavior-disrupting method of the Argentine ant scientific name: Linepithema humile).
2. Description of the Related Art
The Argentine ant (Linepithema humile) is, as its name suggests, the ant coming from South American countries such as Argentine. Its distribution is spreading to North America, Europe, Africa and Australia owing to the human activities and circulation of commodities accompanying, for example, trade. The Argentine ant is a difficult-to-control insect whose problems such as damage to agricultural crops, invasion into houses as a noxious ant and expulsion of endemic ant species causing deterioration in the ecosystem have recently become apparent in Japan.
Invasion to Asian countries were not known until the recent years. In 1993, the inhabitation of the Argentine ants was confirmed for the first time in Hiroshima Prefecture. Since then, they have been discovered in Yamaguchi Prefecture and Hyogo Prefecture. They are active at a temperature range of from 5 to 35° C. so that their distribution may spread mainly on the Pacific side of the western Japan and eastern Japan. The main problem in Japan at present is that they invade into houses as noxious ants. Owing to their strong reproductive power and active behavioral characteristics, expulsion of endemic ant species has been observed in their hot spot and they have already had an adverse effect on the ecosystem. In future, there is a fear of their causing damage to agricultural crops which have already been a problem overseas.
Insecticides or toxic baits are used for controlling Argentine ants because they have a high reproductive power and their active area is wide. In addition to their insufficient effects, frequent use of insecticides has a bad influence on human bodies and moreover, it may destruct the balance of ecosystem including the relationship with natural enemies. There is accordingly an eager demand for the development of a safe controlling method of them.
It should be noted that the main component of a trail pheromone of Argentine ants was identified as Z-9-hexadecenal about 20 years ago (see Cavill, G. W. K., N. W. Davies, and F. J. McDonald (1980) J. Chem. Ecol., 6, 371-384.)